US4685012A - Magnetic head with anisotropy in plane of core ports - Google Patents
Magnetic head with anisotropy in plane of core ports Download PDFInfo
- Publication number
- US4685012A US4685012A US06/793,027 US79302785A US4685012A US 4685012 A US4685012 A US 4685012A US 79302785 A US79302785 A US 79302785A US 4685012 A US4685012 A US 4685012A
- Authority
- US
- United States
- Prior art keywords
- magnetic
- core parts
- core
- magnetic head
- plane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3176—Structure of heads comprising at least in the transducing gap regions two magnetic thin films disposed respectively at both sides of the gaps
- G11B5/3179—Structure of heads comprising at least in the transducing gap regions two magnetic thin films disposed respectively at both sides of the gaps the films being mainly disposed in parallel planes
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/147—Structure or manufacture of heads, e.g. inductive with cores being composed of metal sheets, i.e. laminated cores with cores composed of isolated magnetic layers, e.g. sheets
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/187—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features
- G11B5/21—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features the pole pieces being of ferrous sheet metal or other magnetic layers
Definitions
- the invention relates to a magnetic head having a core of a magnetizable material around a part of which a coil is provided.
- the transducing gap is formed between two core parts of an amorphous ferromagnetic metal.
- Such a magnetic head is known from Japanese Patent Publication Kokai No. 58-147818.
- Each core part in the known head consists of a stack of laminations of amorphous ferromagnetic material glued together. Before the stacks of laminations are combined to form a head they are subjected to a thermal treatment in a magnetic field perpendicular to the plane of the core parts, which results in a magnetic anisotropy direction perpendicular to the plane of the core parts. This has a favourable effect on the magnetic permeability.
- the measure at the known magnetic head does not give an optimum result.
- a pair of laminar core parts are of a magnetically anisotropic, amorphous ferromagnetic metal and have a magnetic anisotropy direction which is in the plane of the core parts and encloses an angle ⁇ with the direction in which magnetic flux traverses the core parts during operation.
- ⁇ is preferably in the range from 45° to 90°.
- the invention furthermore relates in particular to magnetic heads having core parts of amorphous alloys comprising iron, cobalt, boron and silicon.
- the desired anisotropy direction in the plane of the core parts can be realized by subjecting the core parts to a thermal treatment in the presence of a magnetic field which is parallel to the plane of the core parts and which has a direction which is desired with respect to the axis of the core parts.
- the time and the temperature of the thermal treatment, as well as the strength of the magnetic field, are selected in accordance with the type of amorphous ferromagnetic metal. It is important on the one hand that the magnetic head anisotropy is low for the benefit of a high permeability and that on the other hand the anisotropy is still sufficiently high to stabilise the desired anisotropy direction.
- FIG. 1 is a graph showing the frequency-dependence of the real component ⁇ ' of the magnetic permeability
- FIG. 2 is a graph showing the frequency dependence of the imaginary component ⁇ " of two cores of an amorphous ferro magnetic metal with the anisotropy direction in the plane of the core (curve a) and perpendicularly to the plane of the core (curve b), respectively.
- FIG. 3 shows a magnetic head having a core of an amorphous ferromagnetic metal.
- FIG. 4 is an elevation and FIG. 5 is a cross-sectional view of the core of the magnetic head shown in FIG. 3 during manufacture.
- FIG. 6 shows a magnetic head having two core parts of an amorphous ferromagnetic metal which are parallel to a magnetic tape to be moved past the magnetic head during operation.
- FIG. 7a shows a magnetic head having two core parts of an amorphous ferromagnetic metal which are perpendicular to a magnetic tape to be moved past the magnetic head during operation.
- FIGS. 7b and 7c show the core parts of the FIG. 7a magnetic head during manufacture.
- Two cores of an amorphous ferromagnetic metal having the composition Co 70 .3 Fe 4 .7 Si 15 B 10 , thickness 14 ⁇ m, width 1 mm, length 5 mm were subjected to a thermal treatment for 10 minutes while simultaneously applying a magnetic field having a strength which is sufficient to saturate the cores magnetically.
- One core was subjected at a temperature of 350° C. to a magnetic field having a strength of 75 kA/m in the plane of the core, perpendicular to the longitudinal axis, to realize an in-plane magnetic anisotropy (curve "a") perpendicular to the longitudinal axis.
- the other core was subjected at a temperature of 350° C.
- the effect on which the invention is based can be used in magnetic heads in various manners.
- FIG. 3 shows a magnetic head 1 of the sandwich type.
- Magnetic head 1 consists of two halves each constructed from two substrates 2, 3 and 4, 5 respectively, for example of glass, between which core parts 6 and 7, respectively, of amorphous ferromagnetic metal have been provided.
- a transducing gap 8 is formed between the core parts 6, 7.
- a coil 9 is provided around core part 6.
- the thickness of the core parts 6, 7 is, for example, 15 ⁇ m with an overall width w of the magnetic head 1 of 200 ⁇ m.
- the core parts 6, 7 may alternatively consist of a laminate of, for example, three sub-core parts of each 5 ⁇ m thickness.
- FIGS. 4 and 5 show how this is realized in the core parts 6, 7 of the magnetic head 1 of FIG. 3.
- the core parts are subjected to a magnetic field which is generated by the permanent magnets 11 and 12.
- Permanent magnet 11 fits around the core parts 6, 7 and permanent magnet 12 fits in the coil chamber 10 (FIG. 4).
- the core parts 6, 7 are provided at the level of the ends of the magnets 11, 12 (FIG. 5).
- FIGS. 4 and 5 indicate the local direction of the magnetic anisotropy after the thermal treatment.
- the flux path during operation is shown diagrammatically by 13 (FIG. 4). In the manner described it is hence possible to induce an in-plane anisotropy in the core parts with a direction which locally is perpendicular to the path of the magnetic flux.
- FIG. 6 shows an alternative magnetic head 14 in which it is simpler to adjust the direction of the in-plane magnetic anisotropy perpendicularly to the path of the magnetic flux.
- Magnetic head 14 consists of two halves each constructed from ferrite core parts 15 and 16, respectively, and core parts 17 and 18, respectively, of an amorphous ferromagnetic metal. The two halves are combined by means of an adhesive while forming a rear gap 19 and a transducing gap 20.
- the core parts 17 and 18 are subjected to a magnetic field H having such a direction that the core parts 17 and 18 after the thermal treatment show an inplane magnetic anisotropy having a direction as indicated by the arrows 21 and 22.
- the direction of the in-plane magnetic anisotropy hence is perpendicular to the direction of the parts of the magnetic flux.
- a coil 23 is provided around the core parts 15 and 16.
- a magnetic tape 24 is moved past the magnetic head 14 so as to produce a magnetic flux-coupling relationship with the transducing gap 20.
- the core parts 17, 18 of amorphous metal hence are parallel to the plane of the magnetic tape 24.
- FIG. 7a shows a magnetic head 25 having a rear yoke 26 of ferrite.
- Two pole shoes each constructed from two substrates 27, 28 and 29, 30, respectively, between which core parts 31 and 32, respectively, of an amorphous ferromagnetic metal have been interposed are provided on the rear yoke 26.
- the substrates 27, 28, 29, 30 which may have a height h of a few tens of a millimeter are, for example, of glass.
- Core part 31 which, just as core part 32, may have a thickness of, for example, 5, 10 15 or 20 ⁇ m, has been subjected to a thermal treatment in a magnetic field H having such a direction that core part 31 shows an in-plane magnetic anisotropy with a direction as indicated by the arrow 33 (FIG. 7b).
- the angle between this direction and the direction of the magnetic flux which traverses the core part 31 during operation varies with the place and roughly assumes values in the range from approximately 45° to approximately 90°.
- Core part 32 has been subjected to a thermal treatment in a magnetic field H 2 with such a direction that core part 32 shows an in-plane magnetic anisotropy with a direction as indicated by arrow 34 (FIG. 7c).
- core part 31 interposed between the substrates 27 and 28 is placed opposite to the core part 32 interposed between the substrates 29 and 30 and is bonded thereto by means of an adhesive while forming a transducing gap 35.
- the magnetic head 25 is completed by a coil 36 provided around the core parts 31 and 32.
- the core parts 31, 32 are provided so as to be perpendicular with respect to the plane of a magnetic tape 37 to be moved past the magnetic head 25 during operation.
- This construction has advantages with respect to the magnetic head shown in FIG. 6 as regards detrition.
- the FIG. 7 magnetic head is easier to manufacture.
Abstract
Description
Claims (4)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL8403595A NL8403595A (en) | 1984-11-27 | 1984-11-27 | MAGNETIC HEAD WITH CORE PARTS OF AMORF FERROMAGNETIC METAL. |
NL8403595 | 1984-11-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
US4685012A true US4685012A (en) | 1987-08-04 |
Family
ID=19844816
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/793,027 Expired - Fee Related US4685012A (en) | 1984-11-27 | 1985-10-30 | Magnetic head with anisotropy in plane of core ports |
Country Status (5)
Country | Link |
---|---|
US (1) | US4685012A (en) |
EP (1) | EP0185406B1 (en) |
JP (1) | JPH0734245B2 (en) |
DE (1) | DE3581715D1 (en) |
NL (1) | NL8403595A (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4011694A1 (en) * | 1989-04-17 | 1990-10-18 | Mitsubishi Electric Corp | MAGNETIC RECORDING DEVICE |
US4970616A (en) * | 1988-08-17 | 1990-11-13 | Digital Equipment Corporation | Recording head to minimize undershoots in readback pulses |
US5168410A (en) * | 1989-10-20 | 1992-12-01 | Seagate Technology Inc. | Thin film core of Co-Fe-B alloy |
EP1067567A1 (en) * | 1999-01-26 | 2001-01-10 | Hitachi Metals, Ltd. | Diskette type memory card adapter, magnetic sensor therefor magnetic core, method for manufacturing the magnetic core |
US20020171974A1 (en) * | 1999-12-30 | 2002-11-21 | Dugas Matthew P. | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads |
US20040120064A1 (en) * | 2002-06-19 | 2004-06-24 | Dugas Matthew P. | Optical path for a thermal-assisted magnetic recording head |
US20060061906A1 (en) * | 1999-12-30 | 2006-03-23 | Advanced Research Corporation | Wear pads for timing-based surface film servo heads |
US8068301B2 (en) | 2008-03-28 | 2011-11-29 | Advanced Research Corporation | Magnetic media formed by a thin film planar arbitrary gap pattern magnetic head |
US8144424B2 (en) | 2003-12-19 | 2012-03-27 | Dugas Matthew P | Timing-based servo verify head and magnetic media made therewith |
US8416525B2 (en) | 2004-05-04 | 2013-04-09 | Advanced Research Corporation | Magnetic media formatted with an intergrated thin film subgap subpole structure for arbitrary gap pattern magnetic recording head |
US8767331B2 (en) | 2009-07-31 | 2014-07-01 | Advanced Research Corporation | Erase drive system and methods of erasure for tape data cartridge |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4868698A (en) * | 1987-03-05 | 1989-09-19 | Matsushita Electric Industrial Co., Ltd. | Magnetic head |
FR2622335B1 (en) * | 1987-10-27 | 1990-01-26 | Thomson Csf | MAGNETIC HEAD FOR READING RECORDING AND METHOD OF MAKING |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5447616A (en) * | 1977-09-22 | 1979-04-14 | Hitachi Ltd | Amorphous alloy magnetic head core |
US4411716A (en) * | 1980-07-11 | 1983-10-25 | Hitachi, Ltd. | Amorphous alloys for magnetic head core and video magnetic head using same |
US4450494A (en) * | 1980-09-22 | 1984-05-22 | Hitachi Ltd. | Magnetic head |
US4488195A (en) * | 1981-03-20 | 1984-12-11 | Matsushita Electric Industrial Co., Ltd. | Magnetic head and method of producing same |
US4578728A (en) * | 1981-12-09 | 1986-03-25 | Matsushita Electric Industrial Co., Ltd. | Magnetic head |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3986210A (en) * | 1973-02-20 | 1976-10-12 | Matsushita Electric Industrial Co., Ltd. | Magnetic head device using printed circuit techniques |
US4236946A (en) * | 1978-03-13 | 1980-12-02 | International Business Machines Corporation | Amorphous magnetic thin films with highly stable easy axis |
JPS599157A (en) * | 1982-07-08 | 1984-01-18 | Sony Corp | Heat treatment of amorphous magnetic alloy |
JPH061729B2 (en) * | 1983-01-17 | 1994-01-05 | 株式会社日立製作所 | Magnetic film and magnetic head using the same |
JPS59217218A (en) * | 1983-05-25 | 1984-12-07 | Hitachi Ltd | Magnetic head using amorphous alloy and its production |
JPS61127103A (en) * | 1984-11-22 | 1986-06-14 | Sony Corp | Manufacture of magnetic head |
-
1984
- 1984-11-27 NL NL8403595A patent/NL8403595A/en not_active Application Discontinuation
-
1985
- 1985-10-30 US US06/793,027 patent/US4685012A/en not_active Expired - Fee Related
- 1985-11-12 DE DE8585201853T patent/DE3581715D1/en not_active Expired - Lifetime
- 1985-11-12 EP EP85201853A patent/EP0185406B1/en not_active Expired
- 1985-11-25 JP JP60262705A patent/JPH0734245B2/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5447616A (en) * | 1977-09-22 | 1979-04-14 | Hitachi Ltd | Amorphous alloy magnetic head core |
US4411716A (en) * | 1980-07-11 | 1983-10-25 | Hitachi, Ltd. | Amorphous alloys for magnetic head core and video magnetic head using same |
US4450494A (en) * | 1980-09-22 | 1984-05-22 | Hitachi Ltd. | Magnetic head |
US4488195A (en) * | 1981-03-20 | 1984-12-11 | Matsushita Electric Industrial Co., Ltd. | Magnetic head and method of producing same |
US4578728A (en) * | 1981-12-09 | 1986-03-25 | Matsushita Electric Industrial Co., Ltd. | Magnetic head |
Cited By (31)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4970616A (en) * | 1988-08-17 | 1990-11-13 | Digital Equipment Corporation | Recording head to minimize undershoots in readback pulses |
US5363251A (en) * | 1989-04-17 | 1994-11-08 | Mitsubishi Denki Kabushiki Kaisha | Magnetic recorIding device |
DE4011694A1 (en) * | 1989-04-17 | 1990-10-18 | Mitsubishi Electric Corp | MAGNETIC RECORDING DEVICE |
US5168410A (en) * | 1989-10-20 | 1992-12-01 | Seagate Technology Inc. | Thin film core of Co-Fe-B alloy |
US5372698A (en) * | 1989-10-20 | 1994-12-13 | Seagate Technology, Inc. | High magnetic moment thin film head core |
EP1067567A4 (en) * | 1999-01-26 | 2003-03-12 | Hitachi Metals Ltd | Diskette type memory card adapter, magnetic sensor therefor magnetic core, method for manufacturing the magnetic core |
EP1067567A1 (en) * | 1999-01-26 | 2001-01-10 | Hitachi Metals, Ltd. | Diskette type memory card adapter, magnetic sensor therefor magnetic core, method for manufacturing the magnetic core |
US7948705B2 (en) | 1999-12-30 | 2011-05-24 | Advanced Research Corporation | Method of making a multi-channel time based servo tape media |
US7701665B2 (en) | 1999-12-30 | 2010-04-20 | Advanced Research Corporation | Wear pads for timing-based surface film servo heads |
US8542457B2 (en) | 1999-12-30 | 2013-09-24 | Advanced Research Corporation | Method of making a multi-channel time based servo tape media |
US6894869B2 (en) | 1999-12-30 | 2005-05-17 | Advanced Research Corporation | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads |
US20050275968A1 (en) * | 1999-12-30 | 2005-12-15 | Dugas Matthew P | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads |
US8437103B2 (en) | 1999-12-30 | 2013-05-07 | Advanced Research Corporation | Multichannel time based servo tape media |
US20060061906A1 (en) * | 1999-12-30 | 2006-03-23 | Advanced Research Corporation | Wear pads for timing-based surface film servo heads |
US8254052B2 (en) | 1999-12-30 | 2012-08-28 | Advanced Research Corporation | Method of making a multi-channel time based servo tape media |
US20080024913A1 (en) * | 1999-12-30 | 2008-01-31 | Dugas Matthew P | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads |
US7525761B2 (en) | 1999-12-30 | 2009-04-28 | Advanced Research Corporation | Method of making a multi-channel time based servo tape media |
US20020171974A1 (en) * | 1999-12-30 | 2002-11-21 | Dugas Matthew P. | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads |
US6496328B1 (en) * | 1999-12-30 | 2002-12-17 | Advanced Research Corporation | Low inductance, ferrite sub-gap substrate structure for surface film magnetic recording heads |
US20100002332A1 (en) * | 2002-06-19 | 2010-01-07 | Dugas Matthew P | Optical Path for a Thermal-Assisted Magnetic Recording Head |
US7944647B2 (en) | 2002-06-19 | 2011-05-17 | Advanced Research Corporation | Optical path for a thermal-assisted magnetic recording head |
US7532435B2 (en) | 2002-06-19 | 2009-05-12 | Advanced Research Corporation | Optical path for a thermal-assisted magnetic recording head |
US20070008659A1 (en) * | 2002-06-19 | 2007-01-11 | Advanced Research Corporation | Optical path for a thermal-assisted magnetic recording head |
US6996033B2 (en) | 2002-06-19 | 2006-02-07 | Advanced Research Corporation | Optical path for a thermal-assisted magnetic recording head |
US20040120064A1 (en) * | 2002-06-19 | 2004-06-24 | Dugas Matthew P. | Optical path for a thermal-assisted magnetic recording head |
US8144424B2 (en) | 2003-12-19 | 2012-03-27 | Dugas Matthew P | Timing-based servo verify head and magnetic media made therewith |
US8416525B2 (en) | 2004-05-04 | 2013-04-09 | Advanced Research Corporation | Magnetic media formatted with an intergrated thin film subgap subpole structure for arbitrary gap pattern magnetic recording head |
US8068301B2 (en) | 2008-03-28 | 2011-11-29 | Advanced Research Corporation | Magnetic media formed by a thin film planar arbitrary gap pattern magnetic head |
US8068300B2 (en) | 2008-03-28 | 2011-11-29 | Advanced Research Corporation | Thin film planar arbitrary gap pattern magnetic head |
US8068302B2 (en) | 2008-03-28 | 2011-11-29 | Advanced Research Corporation | Method of formatting magnetic media using a thin film planar arbitrary gap pattern magnetic head |
US8767331B2 (en) | 2009-07-31 | 2014-07-01 | Advanced Research Corporation | Erase drive system and methods of erasure for tape data cartridge |
Also Published As
Publication number | Publication date |
---|---|
JPH0734245B2 (en) | 1995-04-12 |
EP0185406B1 (en) | 1991-02-06 |
DE3581715D1 (en) | 1991-03-14 |
EP0185406A1 (en) | 1986-06-25 |
NL8403595A (en) | 1986-06-16 |
JPS61131213A (en) | 1986-06-18 |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
Owner name: U.S. PHILIPS CORPORATION, 100 E 42ND STREET, NEW Y Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DEWIT, HENDRIK J.;BROUHA, MARCEL;ENZ, ULRICH E.;REEL/FRAME:004505/0328;SIGNING DATES FROM 19851216 TO 19851219 |
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Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
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FPAY | Fee payment |
Year of fee payment: 4 |
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FPAY | Fee payment |
Year of fee payment: 8 |
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REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 19990804 |
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STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |